DESCRIPTION: The NCEP Step 1 Diet is the recommended initial dietary treatment to prevent CHD. However, the effectiveness of the NCEP diet in reducing risk has been questioned because of the modest reductions in total and LDL cholesterol, and its potential to simultaneously lower HDL. As an alternative to the Step 1 Diet, others have advocated a high monounsaturated fatty acid (MUFA) or so-called Mediterranean diet. However, a diet therapy plan based on this diet has not been thoroughly tested in a free-living population. The proposed randomized trial will directly compare the effectiveness of the NCEP Step 1 Diet and a high MUFA Diet in reducing CHD risk factors in a population, defined by NCEP ATP II, to be at high risk for future development of CHD. 120 participants will be studied during a 2-week baseline period and then randomized to one of the two intervention groups for 24 weeks. The outcome variables will be blood lipids, hemostasis factors, blood pressure, body weight and composition, and indices of dietary compliance.